The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Electronic communication equipment today usually contains two or more radio transceivers that can operate concurrently. A long-term evolution (LTE) smart phone or an LTE mobile hotspot can be equipped with an LTE radio, a wireless fidelity (WIFI) radio, a Bluetooth (BT) radio, and a global navigation satellite system (GNSS) radio, all in the same device. When the LTE working frequency is close to the WIFI/BT frequency on the same LTE smart phone, for instance, IDC interference may occur. More specifically, LTE radio transceivers can operate under Band 40 (2300 MHz-2400 MHz) and Band 7 (2500 MHz-2570 MHz). These two LTE bands are adjacent to the industrial, scientific and medical (ISM) band (2400 MHz-2500 MHz) under which the WIFI/BT radio transceivers typically operate. As a result, the LTE radio transceivers and the WIFI/BT radio transceivers on the same device may cause serious IDC interference for each other.
Traditionally, IDC interference is mitigated by radio frequency (RF) techniques, such as filtering or isolation. However, analyses made by the Third Generation Partnership Project (3GPP) showed that current state-of-the-art RF filtering technology cannot provide sufficient interference rejection for certain IDC scenarios. There have also been attempts to address the IDC interference problem by time-division multiplexing (TDM) techniques, such as the Wireless Coexistence Interface (WCI) proposed by the Bluetooth standard group. However, the transmission and signaling protocols defined by WCI is complicated, often requiring complete hardware and software redesign of existing radios. The research and development cost for implementing such a system can be extremely high.